AbstractTranspired metal plate has been widely used as solar collectors in buildings. However, there are only a few studies on heat transfer of transpired plate for solar collector applications. In addition, most of them were based on uniform flow distribution which assumed that air temperature in the plenum is always constant. In this paper, the heat transfer of the system was analy sed through two different airflow directions i.e. normal to the hole (normal flow) and from the bottom to the top in the plenum (vertical flow). From the experimental results, it was found that the contribution of vertical flow in total air temperature rise was 40% and above. Hence, the heat transfer from the back-of-plate to the air in the plenum is inappropriate to be ignored. The theoretical calculation was based on an average value instead of local heat transfer. The thermal performance of the system was also simulated by using the present model and compared with previous study. The results were comparable in terms of heat exchange effectiveness. Hence vertical flow should be included in the thermal performance evaluation when the flow uniformity is uncertain.